Ph.D. in Environmental Toxicology, University of California at Riverside, 1997
Applied and Environmental Microbiology
Molecular Genetics and Biochemistry
Microbial biofilms: understanding microorganisms attached to surfaces. The central focus of research in my laboratory is microbial biofilms, or communities of microorganisms attached to surfaces. Biofilms are widely distributed in nature, and may be beneficial or harmful to humans, depending on the microbes that inhabit them. A common feature to all of our work with biofilms is quantitative analysis of biofilm structure based on biofilms grown in flow cells and imaged by confocal microscopy. This approach allows us to make rigorous examinations of factors affecting biofilm structure, organization and function.
In one project, we found that plant essential oil components can affect biofilm formation, and determined that the plant-derived compound cinnamaldehyde inhibited select types of bacterial quorum sensing, or cell-to-cell communication. A related project determined that expression of luxS, the gene encoding autoinducer-2 (AI-2) synthase, altered biofilm structure and cell fimbriation. A second avenue of research in our laboratory is directed towards understanding cooperative interactions in multispecies biofilms. Using a model system, we investigated a commensal relationship where an antibiotic resistant strain of E. coli could aid the survival of an antibiotic sensitive strain, and found that the benefit was conditional, depending on antibiotic concentration. We are currently using the model to investigate mutualistic interactions that contribute to multiple antibiotic resistance. In a third project that diverged from our work on cooperative interactions, we found that biofilms improved the maintenance of high copy number plasmids and also the production of heterologous protein relative to cells in suspended culture. This novel finding could be a beneficial tool for use in metabolic engineering.
We are currently working on approaches to cultivate multispecies biofilms with defined compositions. We hope to use our newly-developed techniques in our research on cooperative interactions that foster antibiotic resistance, and to build multispecies biofilms that break down mixed wastes.
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